Optical disks, such as a compact disk (CD) and a digital versatile disk (DVD), are widely used in electronic equipment for recording and reproducing audio and video information in a high density format. CDs may be used as a recording medium for storing audio information in a high density format. DVDs may be used as a recording medium for storing video information, since a DVD can store more information in a higher density format than a CD.
To meet various requirements for recording information in a high density format and reproducing it, various kinds of CDs and DVDs have been developed. For example, as optical disks of a CD-group, a CD read-only memory (CD-ROM) disk, a CD-recordable (CD-R) disk, and a CD re-writable (CD-RW) disk have been developed. As optical disks of a DVD-group, a DVD-ROM disk for using a read only memory, a DVD-recordable (DVD-R) disk, a DVD re-recordable (DVD-RW) disk, and a DVD re-writable (DVD-RAM) disk have been developed.
To commonly drive the various optical disks, a multi-drive-type disk apparatus has recently been developed in order to write and read information to and from each of the various types of optical disks.
In order to drive a particular type of optical disk, the multi-drive-type disk apparatus needs to identify a predetermined performance characteristic, such as a data transfer rate, for each of the particular optical disks installed in the disk apparatus. Generally, the optical disks of the CD group have a one-fold speed of 150 kilo-bits per second (“Kb/sec”) as a standard speed of the data transfer rate. Usually, each of the CD-group's optical disks is defined by a respective transfer rate by indicating several times-fold speed of the standard speed. For example, the transfer rate for a CD-ROM is usually indicated as a “12-times speed”. This means that when the disk apparatus reads information from the CD-ROM installed in it, the reading operation is preformed at a maximum transfer rate of 1.8 mega bits per second (1.8 Mb/sec).
Similarly, each of DVD disks in the DVD-group have a one-fold speed of about 1,352 Kb/sec as a standard data transfer rate. A particular transfer rate for each of the DVD disks is also indicated at several times that of the standard speed. For example, a transfer rate for DVD-ROM is indicated as a “16 times-fold speed”. This means that when the disk apparatus reads information from the DVD-ROM optical disk installed in it, it is guarantees to be performed the reading operation is preformed at a maximum transfer rate of about 21,632 Kb/sec.
Usually, such performance characteristics for the respective optical disks are indicated by the maximum transfer rate. For instance, the maximum transfer rate, i.e. performance for a CD-ROM is indicated as a 12 times speed; the performance for a DVD-ROM is indicated as a 4 times-fold speed; similarly, a CD-R is indicated as a 8 times speed; a CD-RW is indicated as a 5 times speed; a DVD-R is indicated as a 2 times speed; and a DVD-RW is indicated as a 1 times speed, i.e., a standard speed. This performance indication is inevitable to determine its accurate speed for performing writing and reading operations to and from a particular type of optical disk.
Conventionally, these data transfer rates for the respective optical disks are indicated by a multiple-fold speed of the standard speed, only in a catalog or a manual for the multi-drive-type disk apparatus. However, there are no indications of the performances or the respective data transfer rates for the respective optical disks on the multi-drive-type disk apparatus itself or on a package for the disk apparatus. Consequently, in every operation time, it needs to refer to the catalog or the manual of the multi-drive-type optical disk apparatus in order to confirm the driving function. The more the multi-drive-type disk apparatus increases its writing and reading functions for supporting drives of optical disks, the more the problem appears for distinguishing each performance for the respective optical disks. Thus, it becomes hard to easily identify a particular performance for a particular optical disk, since its catalog or manual enumerates merely numerals of the multiple-fold speed and characters for indicating types of optical disks.